Many environmental factors can diminish the performance of a lens outdoors. Rain, mist, soot and dust all cause the image to become clouded as the clear parts of the lens are covered up. Because water and dirt also can harm the special coatings on the front surfaces of lenses, it is common practice to cover and protect the front elements of lenses with a clear or UV-blocking glass filter, held in place in front of the lens by a screw-threaded enclosure. But this type of filter cover does not prevent water drops from appearing in the lens image in the rain, or dust from clouding the image in a dust storm. To try to prevent this, the camera can be swathed in a hooded waterproof wrapping, with the lens looking out of a tunnel or awning that helps keep out the rain and dust, but which is not visible within the field of view of the lens. However, this does not entirely protect the lens, especially when the lens is pointed up at the rain, and raindrops can sometimes be seen dripping from the forward edge of the tunnel. The camera operator must always be alert and ready to wipe the lens clear if necessary. And when the lens is a wide-angle lens, the tunnel cannot be long enough to protect the lens and still remain invisible.
As camera systems have evolved to include panoramic and immersive cameras, with lenses that in some cases face in many directions at once, the problem has increased. There is now an even larger area to keep protected from the weather, and almost no invisible areas where the means of protection can be hidden.
As an improved glass filter, the Israeli company Spintec has marketed a clear spinning disk which can be placed in front of a camera lens, which is described in U.S. Pat. No. 6,731,867 “Lens Protection Mechanism”. The rapid spinning of this disk, at 5000 RPM, prevents raindrops from adhering to the disk surface, and keeps the lens image clear. However, this device has a large frame and motor assembly for spinning the disk, and is designed to be used with a single lens that has a relatively narrow field of view. Because of this, it cannot be used for protecting immersive or panoramic cameras, which often have multiple lenses that look in several directions and would always see such a bulky spinning disk mechanism.
The present invention changes the approach to lens protection to include wide-angle and even immersive camera systems, by the use of a specially designed, rapidly spinning clear volumetric enclosure or “shell.” Unlike conventional lens filters, the present invention does not allow the buildup of any raindrops or dust to cloud the lens image. The present invention provides environmental protection from a wide variety of hazards and maintains a clear lens image automatically, without user intervention, and is invisible to camera systems with single or multiple panoramic or immersive camera lenses. In addition, the mechanical rotation of the present invention provides camera stabilization through gyroscopic action, and also the means to cool the camera by blowing air through the protected enclosed space.